Cutaneous Squamous Cell Carcinoma Arising From Hidradenitis Suppurativa and Epidermal Cyst: Clinical Characteristics, Baseline Neutrophil‐To‐Lymphocyte Ratio, and Disease‐Specific Survival in a Retrospective Cohort

ABSTRACT

Cutaneous squamous cell carcinoma (cSCC) may develop in chronic inflammatory settings, but clinicopathological features and outcomes remain poorly defined. To characterize clinical features and disease‐specific survival (DSS) of cSCC arising from HS or EC in a single‐institution cohort, and to assess baseline neutrophil‐to‐lymphocyte ratio (NLR) as a readily available inflammatory marker. We retrospectively reviewed 231 patients with cSCC diagnosed at a tertiary academic center between January 2013 and December 2024. After excluding 36 without baseline NLR data, a total of 195 patients were analyzed. Clinical characteristics, tumor staging, HS severity, baseline NLR, and DSS were evaluated. Of 195 evaluable patients, 8 had cSCC arising from hidradenitis suppurativa (HS), 5 from epidermal cysts (EC), 14 from burn scars, and 168 de novo (primary) cSCC. HS/EC‐associated cSCC showed significantly higher baseline NLR than others ( p  = 0.016). In univariate analysis, primary tumor site, clinical T and N stages, baseline NLR, and HS/EC‐associated lesion were significantly associated with DSS. Burn scar–associated cSCC was not significantly associated with DSS ( p  = 0.60). In multivariate analysis, clinical N and T stage ( p  < 0.05) and HS/EC‐associated cSCC ( p  = 0.020; HR = 4.28, 95% CI, 1.26–14.6) remained independently associated with poorer DSS. In this cohort, cSCC arising from HS or EC was associated with elevated baseline NLR and poorer DSS. These findings suggest that HS/EC‐associated cSCC may represent a clinically recognizable high‐risk subgroup warranting careful surveillance, while the prognostic role of baseline NLR requires validation in larger studies.